Killing two infantry guards, Graff furthered the plot by Lord Garth and Rachan by clearing a secret route for (what could be considered) special-ops forces belonging to Lord Garth. These forces placed an unknown number of explosive devices in the domes of the Sirius V city, Tiantan.

Tiantan was destroyed shortly after, and Graff continued his service with the Legion as it returned to its landhold on the planet Helm. His subterfuge was later discovered by Gray Death commander Grayson Carlyle, when he reported a blown coolant seal on his BattleMech, an Assassin, using the excuse to gain entry to the DropShipPhobos during combat.
Once inside the DropShip, Graff killed many members of the ship's crew and by threatening to remotely trigger the destruction of the other DropShip, the Deimos, gained control of both for Lord Garth and Rachan.
The two DropShips were later freed by Legion forces, and despite Graff's efforts, the Legion gained possession of a copy of the Helm Memory Core, a three-century-old computer containing many Star League-era secrets, ranging from improving crop production to the design of all sorts of technology, equipment and military hardware.